Saturday, September 19, 2009

How to Improve Vaccines

How can scientists engineer a disabled vaccine to make it as potent as a “live” vaccine but as safe as a “killed” vaccine?

Disabled viruses have been effective in the production of vaccines for smallpox and polio. However, for non-viral diseases like tuberculosis and malaria, the immune system is able to recognize that the viruses in these vaccines are disabled, and hence, the immune system will not trigger the anticipated antibody response.

The co-author of a study that suggests a solution to this problem, Daniel Portnoy, a UC Berkeley professor of molecular and cell biology and of public health, explains, “What this says is that the immune system knows the difference between a live bug that's virulent and a dead one that is harmless." Furthermore, Portnoy says that not only is there no immune response, immunity is also suppressed.

To solve this problem, the study suggests getting the microbes to act as if they’re alive. The strategy is to select new bacterial strains that induce the right kind of immune response.

The pathogen seems to take on a personality and these mannerisms within the cell affect how the immune system will respond — “where it goes in the cell, what pathways it interferes with, and how disruptive it is.” A vaccine against these pathogens would need to have an effect of inducing T cell response, a condition that does not happen with currently available vaccines.